Smoke density and toxicity detection system based on development of flame-retardant reinforced nylon halogen-free material

Abstract

The invention relates to the technical field of smoke density and toxicity detection of material development, and discloses a smoke density and toxicity detection system based on flame-retardant reinforced nylon halogen-free material development, which comprises the following steps: configuring a formula for developing a flame-retardant reinforced nylon halogen-free material, and setting parameters of the formula; the meshing period of adjacent thread elements is calculated and grouped, a plurality of sensors are evenly installed in a thread machine barrel, and a sampling point on the thread element is configured for each sensor; generating a time sequence of each sampling point, collecting smoke density and gas component concentration in real time, and extracting periodic characteristic parameters of the sampling points; calculating a comprehensive adhesion index according to the periodic characteristic parameters to execute material adhesion judgment, and calculating adhesion quality after positioning an adhesion position; according to the comprehensive adhesion index, the adhesion quality and the gas component concentration, decision-making and maintenance actions for the double-screw extruder are executed on the basis of a set threshold value, and the production quality, the operation safety and the material utilization efficiency of the double-screw extruder are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smoke density and toxicity detection of material development, in particular to a smoke density and toxicity detection system based on the development of halogen-free flame-retardant reinforced nylon materials. BACKGROUND

[0002] Nylon, as one of the five engineering plastics, is widely used in machine tools, machinery, automobiles, subways and aviation equipment fields, especially in corrugated pipe products. PA1012 has the advantages of toughness, wear resistance and low temperature shrinkage, and MXD6 has high strength, high toughness, low water absorption and good gas barrier property. In order to meet the demand of high strength and high flame retardant performance of corrugated pipe series products, PA1012 / MXD6 composite material needs to be modified.

[0003] The existing flame-retardant nylon material has many problems in actual application. First, although single PA1012 or MXD6 material has certain advantages in strength and toughness, it is easy to appear mechanical performance decline under high load environment, especially the wear resistance and dimensional stability are insufficient, which is difficult to meet the long-term use requirement. The existing technology has obvious defects in the process of processing flame-retardant nylon material in double screw extruder. The inside of screw barrel cannot be directly observed, and the local material adhesion condition is difficult to monitor. The existing detection method mainly depends on the overall smoke density or gas emission measurement, and lacks real-time tracking of the spatial distribution and periodic characteristics of the material adhesion on each screw element inside the screw. It cannot accurately judge the adhesion position and severity. In addition, local adhesion is unpredictable, which may cause screw jamming, material overheating or excessive local smoke generation, but these problems cannot be found or located in advance. The traditional method also lacks quantitative evaluation means for the adhesion material, which leads to the inability to take targeted treatment measures in time in the production process, increases the product quality fluctuation and safety risk.

[0004] The present application provides a smoke density and toxicity detection system based on the development of halogen-free flame-retardant reinforced nylon materials, which solves the problems mentioned in the background art. SUMMARY

[0005] The present application provides a smoke density and toxicity detection system based on the development of halogen-free flame-retardant reinforced nylon materials, which is used to promote the solution of the problems mentioned in the background art.

[0006] The present application provides the following technical scheme: a smoke density and toxicity detection system based on the development of halogen-free flame-retardant reinforced nylon materials, comprising:

[0007] The formula parameter configuration module is used for configuring the formula of developing halogen-free flame-retardant reinforced nylon materials, and setting the parameters of the formula.

[0008] A sampling point configuration module is configured to calculate the meshing period of adjacent thread elements and group them, and install multiple sensors in the thread barrel uniformly, and configure sampling points on the thread elements for each sensor;

[0009] A sampling and period feature extraction module is configured to generate a time series of each sampling point, collect smoke density and gas component concentration in real time, and extract period feature parameters of the sampling points;

[0010] An adhesion determination and positioning module is configured to perform material adhesion determination according to the period feature parameters and calculate the adhesion quality after locating the adhesion position;

[0011] A decision and maintenance action module is configured to perform decision and maintenance actions for the twin-screw extruder based on the set threshold values according to the comprehensive adhesion index, adhesion quality and gas component concentration.

[0012] Optionally, the formula parameter configuration module is configured to configure the formula of developing the halogen-free flame-retardant reinforced nylon material and set the proportion of the formula, including:

[0013] The weight of the halogen-free flame-retardant reinforced nylon material is set to 1;

[0014] The formula and weight of the halogen-free flame-retardant reinforced nylon material are respectively PA1012 resin 0.25-0.50, MXD6 resin 0.20-0.40, wollastonite whisker 0.25-0.40, compounded flame retardant 0.15-0.20, toughening agent 0.005-0.05, glass fiber 0.15-0.30, antioxidant 0.005-0.02, and lubricant 0.005-0.02;

[0015] The melting temperature of the PA1012 resin is 260±5℃, and the density is 1.03g / cm3;

[0016] The melting temperature of the MXD6 resin is 280-300℃, and the density is ≥1.32g / cm3;

[0017] The wollastonite whisker is obtained by surface treatment of a coupling agent, is white, has an aspect ratio of 2-20, and a density of 2.9g / cm3, and the toughening agent is a maleic anhydride modified polyolefin elastomer;

[0018] The compounded flame retardant is respectively aluminum hypophosphite 0.10-0.12 and melamine polyphosphate 0.05-0.08.

[0019] Optionally, the sampling point configuration module is configured to calculate the meshing period of adjacent thread elements and group them, and install multiple sensors in the thread barrel uniformly, and configure sampling points on the thread elements for each sensor, including:

[0020] The threaded element is used to configure the screw, and the two screws are respectively referred to as screw one and screw two;

[0021] For any threaded element:

[0022] Obtain the pitch of the threaded element and rotational speed ;

[0023] Calculate axial thrust speed ;

[0024] Get the length of the threaded element Calculate the transmission cycle of the threaded element. ;

[0025] The transmission cycles of adjacent threaded elements located on screw one and screw two are denoted as follows: and ;

[0026] Adjacent threaded elements are screwed together, take and Least Common Multiple As the meshing cycle;

[0027] On any screw, adjacent threaded elements with equal meshing periods are grouped together;

[0028] Each set of threaded elements is equipped with a single sensor, with the sensor positioned directly opposite the centerline of the two screws;

[0029] Set the number of samples taken by the sensor during the engagement cycle. The sampling frequency of the sensor ;

[0030] At sampling time The rotation phase of the threaded element corresponding to sampling point k is ,in, This represents the initial phase of the threaded element. Modulo operation.

[0031] Optionally, the sampling and periodic feature extraction module is used to generate a time series for each sampling point, collect smoke density and gas component concentration in real time, and extract periodic feature parameters of the sampling points, including:

[0032] For any sensor:

[0033] The smoke density S(k) at sampling point k in each engagement cycle is obtained by the sensor and then denoised.

[0034] Plot a two-dimensional curve of smoke density, and follow... By dividing the two-dimensional curve into units on the horizontal axis, multiple sets of periodic smoke densities are obtained, and the peak value of the smoke density S(k) for each period is obtained. ;

[0035] Set peak threshold Obtain within any period Maximum smoke density Extract the corresponding smoke density phase ;

[0036] Mapping Given a unit vector in the complex plane, calculate the phase concentration of the smoke density. , It is a unit vector. The number of sampling points;

[0037] Obtain arbitrary sampling points of the next set of threaded elements along the material transport direction. Obtain sampling points smoke density ;

[0038] Calculate sampling point k and sampling point Maximizing discrete cross-correlation , For the smoke to be transferred from sampling point k to sampling point Duration Used to measure smoke density According to different durations Alignment smoke density to similar and ;

[0039] for The smoke density at sampling point k at time k. for Time sampling point Smoke density;

[0040] Calculate the transmission velocity of smoke density along the material transport direction. , For sampling point k to sampling point Euclidean distance.

[0041] Optionally, the real-time acquisition of smoke density and gas component concentration, and the extraction of periodic characteristic parameters of sampling points, further includes:

[0042] Obtain the composition of all gases at sampling point k collected by the sensor;

[0043] For any gas composition:

[0044] Obtain the concentration of gas components Calculate the average concentration at sampling point k according to the time series. ;

[0045] Obtain the concentration difference of adjacent gas components in the time series. ;

[0046] Calculate the rate of increase in concentration .

[0047] Optionally, the adhesion determination and positioning module is used to calculate a comprehensive adhesion index based on periodic characteristic parameters to perform material adhesion determination, including:

[0048] For sampling point K throughout the entire detection process:

[0049] Calculate the difference in concentration increase rate and then calculate the mean. ;

[0050] Obtain the torque variation of each threaded element within the threaded element group and calculate the average value. ;

[0051] Obtain the current change of the screw ;

[0052] The periodic characteristic parameter ,include , , The periodic feature parameters are normalized and updated to the normalized values.

[0053] Set the feature correlation matrix The feature correlation matrix is ​​used to set a weight coefficient for each element in the periodic feature parameters to complete feature interaction;

[0054] Using the feature correlation matrix For periodic characteristic parameters Cross-weighted , ;

[0055] Mapping the cross-weighted result to a nonlinear function , ,in, To adjust the parameters and control the steepness of the response, For the cumulative effect of multiple features, The expression is converted into exponential form to ensure... ;

[0056] Will Normalize and update to the normalized value;

[0057] Calculate the combined adhesion index upstream and downstream of the sampling point ,in, The nonlinear function at any sampling point along the material transport direction. These are spatial adjustment parameters used to control the degree of influence from the neighborhood.

[0058] For any sampling point within the group, obtain the smoke density difference between the sampling points. ;

[0059] Set adhesion index threshold Sum and difference thresholds

[0060] If sampling points exist simultaneously and If so, it can be preliminarily determined that there is material adhering to it;

[0061] Obtain the comprehensive adhesion index of all sampling points within a single group and calculate the mean. ;

[0062] Continue to determine If so, it is determined that the material is attached to a single set of threaded elements.

[0063] Optionally, calculating the adhesion quality after locating the adhesion position includes:

[0064] Along the material transport direction, if there are consecutive single sets of threaded elements with material attachment, then the axial attachment section is located as consecutive single sets of threaded elements with material attachment.

[0065] Obtain the phase of the maximum smoke density at each sampling point in the axial attachment section, and calculate the mean value. ;

[0066] Set phase spread ;

[0067] Calculate the phase concentration interval ;

[0068] By acquiring sampling points where the smoke density phase exceeds the phase concentration interval, the circumferential attachment section is obtained;

[0069] Sampling points for the attached material are located by the axial attachment section and the circumferential attachment section;

[0070] Setting the material adhesion coefficient It is used to reflect the sensitivity of changes in smoke density to the conversion of matter;

[0071] Calculate the mass of the attached material at the sampling point. , This represents the total sampling time.

[0072] Optionally, the decision-making and maintenance action module is used to perform decision-making and maintenance actions for the twin-screw extruder based on a set threshold according to the comprehensive adhesion index, adhesion quality, and gas component concentration, including:

[0073] Setting gas component thresholds ;

[0074] Obtain the concentration of gaseous components harmful to the human body. If the sampling point k If this occurs, immediately suspend the twin-screw extruder and issue an alarm;

[0075] The comprehensive adhesion index, adhesion quality, and gas component concentration are normalized and updated to normalized values;

[0076] Set weight coefficients ;

[0077] Calculate risk score ;

[0078] Set risk threshold and duration threshold ;

[0079] like And lasting longer than If necessary, the twin-screw extruder should be shut down for maintenance.

[0080] like And lasting longer than If so, notify maintenance personnel to check.

[0081] The present invention has the following beneficial effects:

[0082] 1. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon materials, exhibits improved dispersion of modified wollastonite whiskers, enabling reinforcement and modification of PA1012 / MXD6 composites. Furthermore, it demonstrates good interfacial compatibility with the resin, enhancing the mechanical properties of the PA1012 / MXD6 composite. The compounded flame retardant decomposes at high temperatures to generate aluminum phosphate, promoting carbonization of the material. Simultaneously, the nitrogen-based flame retardant decomposes to release inert gases, diluting flammable gases and forming an expanded carbon layer, which is more conducive to blocking heat conduction between the polymer and heat source components. Maleic anhydride-grafted polyolefin elastomers have excellent toughening effects on PA1012 / MXD6 composites. The added lubricant allows for more uniform dispersion of glass fiber and flame retardant within the composite, effectively improving the mechanical properties and flame retardant effect of the composite.

[0083] 2. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon, achieves multi-parameter coordinated detection of smoke density and harmful gas concentration during the processing of flame-retardant materials. It simultaneously acquires optical scattering signals and chemical gas signals within the same device, forming a time-synchronized data link. It can continuously record real-time smoke density changes during screw conveying, melting, and exhaust stages, and fuse these changes with harmful gas component concentration signals to achieve a comprehensive assessment of flame retardant decomposition, thermal cracking, and localized carbonization adhesion. Compared to traditional systems that only monitor smoke volume or a single toxicity indicator, it improves the sensitivity for identifying abnormal conditions such as "early adhesion," "localized blockage," and "incomplete thermal decomposition of materials." With a fast detection response speed, it can be integrated into existing extruders or molding equipment, offering significant engineering value for ensuring equipment stability, optimizing flame-retardant formulations, and assessing safety.

[0084] 3. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon, utilizes the periodic phase distribution of the smoke density signal to determine flow field stability and adhesion zones. By calculating the concentration of the smoke density phase vector on the unit circle, the stability of the periodic signal can be quantified. When material adhesion or local disturbances occur, the phase distribution immediately diverges, and the concentration decreases. Without additional image sampling, statistical methods are used to identify "circumferential adhesion" and "periodic disturbances." It is unaffected by light intensity fluctuations and can detect trends of periodic instability within a short sampling window. The system uses a periodic difference method to calculate the gas concentration growth rate within adjacent sampling periods to characterize the release rate of flame-retardant material decomposition products. By combining calculations with the meshing cycle, the concentration change results are strictly aligned with the mechanical motion rhythm.

[0085] 4. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon, proposes a threaded element transmission and meshing cycle modeling method. Based on geometric parameters such as pitch, rotational speed, and length, it establishes an analytical relationship between material transmission speed and meshing cycle. By calculating the least common multiple period, it achieves time synchronization of the twin-screw meshing motion, ensuring alignment of smoke density and gas signals within a precise periodic framework. Coupled with the mechanical motion and signal sampling mechanism, the output periodic parameters can be used to control the sampling frequency, schedule the data window, and define the phase concentration interval, improving the temporal resolution and repeatability of adhesion detection. High-precision timing control is achieved solely through motion parameters without adding additional sensors.

[0086] 5. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon, weights and fuses multiple detection signals through a feature correlation matrix to form a composite feature vector. This vector simultaneously expresses the coupling relationship between different physical signals, eliminating single-signal misjudgments. After mapping, a stable normalized index is formed, suppressing the influence of noise on the judgment results. A multi-dimensional logical conjunction model is constructed, ensuring that the adhesion signal is amplified and output only when it reaches consistency across multiple dimensions, thus significantly improving detection accuracy. The adhesion quality calculation method is based on the integration of the comprehensive adhesion index, adhesion coefficient, and smoke density signal to calculate the equivalent quality of the adhesion area. A quantitative correspondence is established between optical signals and physical quantities, transforming adhesion detection from a qualitative description to quality estimation. The adhesion coefficient is used to map smoke density units to mass, achieving cross-domain calibration. Time integration reflects the cumulative trend of the adhesion layer over operating time.

[0087] 6. This smoke density and toxicity detection system, developed based on flame-retardant reinforced halogen-free nylon, proposes a risk-based maintenance decision-making method. Using adhesion index, adhesion quality, and gas concentration as inputs, a comprehensive risk score is generated through weighted coefficients to trigger maintenance commands (prompts, speed limits, or shutdowns). This achieves a closed-loop process from detection to decision-making, automatically taking safety measures before adhesion risk accumulates to a threshold. By dynamically adjusting the weights, alarm sensitivity can be adaptively controlled based on material type or equipment load. Compared to traditional timed maintenance mechanisms, this significantly reduces unnecessary downtime and proactively prevents equipment failures or harmful gas leaks caused by adhesion, improving overall operational safety and intelligence. Attached Figure Description

[0088] Figure 1 This is a schematic diagram of the system modules of the present invention.

[0089] Figure 2 This is a top view of the threaded element of the present invention.

[0090] Figure 3 This is a side view of the threaded element of the present invention. Detailed Implementation

[0091] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0092] Example 1, refer to Figure 1 A smoke density and toxicity detection system developed based on flame-retardant reinforced halogen-free nylon materials includes:

[0093] In a twin-screw extruder, the main function of the screw is to propel solid plastic granules along the screw axis while simultaneously mixing and shearing the material. When flame-retardant nylon material is added to the screw barrel, the screw propels the material forward through the meshing of the threaded elements during rotation. The barrel is typically equipped with a heating system (such as an electric heating coil or oil heating jacket) to gradually heat the material to its melting temperature range by controlling the temperature. As the temperature rises, the material transitions from a solid to a viscous molten state, its viscosity decreases, and the screw can generate a shearing and mixing effect during transport, further improving the material's uniformity and flowability. During this process, the material is continuously compressed, stretched, and sheared along the rotating threaded grooves of the screw, ensuring it is fully heated and melts uniformly. Simultaneously, the flow of the molten material is influenced by the thread geometry, pitch, and rotational speed, creating a complex local flow field. In the unseen interior of the screw barrel, this molten flow may experience localized stagnation or adherence to the surface of the threaded elements, especially noticeable when processing high-viscosity or high-filler materials. If such localized adhesion cannot be detected and addressed in real time, it may lead to material deterioration, smoke generation, or screw blockage, affecting product quality and production safety.

[0094] The formulation parameter configuration module is used to configure the formulation for developing flame-retardant reinforced halogen-free nylon materials and to set the formulation ratios, including:

[0095] The weight of the flame-retardant reinforced halogen-free nylon material is set to 1.

[0096] The formulation and weight of the flame-retardant reinforced nylon halogen-free material are as follows: PA1012 resin 0.25-0.50, MXD6 resin 0.20-0.40, wollastonite whiskers 0.25-0.40, compound flame retardant 0.15-0.20, toughening agent 0.005-0.05, glass fiber 0.15-0.30, antioxidant 0.005-0.02, lubricant 0.005-0.02;

[0097] The PA1012 resin has a melting temperature of 260±5℃ and a density of 1.03g / cm3;

[0098] The MXD6 resin has a melting temperature of 280-300℃ and a density ≥1.32g / cm3;

[0099] The wollastonite whiskers are obtained by surface treatment with a coupling agent, are white, have an aspect ratio of 2-20, and a density of 2.9 g / cm3. The toughening agent is maleic anhydride-modified polyolefin elastomer.

[0100] The compound flame retardants are aluminum hypophosphite 0.10-0.12 and melamine polyphosphate 0.05-0.08.

[0101] The preparation method of the PA1012 / MXD6 composite material includes: adding the granular material from each component to a high-speed mixer, then adding various powdered additives, mixing at high speed for 2-10 minutes, then switching to low-speed operation and discharging the material; adding the resulting mixture to a twin-screw extruder for melt extrusion granulation, wherein the melt extrusion temperature is controlled at 255-275℃. Preferably, the length-to-diameter ratio of the twin-screw extruder is 44:1.

[0102] The processing temperatures of each temperature zone of the twin-screw extruder are controlled at 250℃, 270℃, 270℃, 270℃, 260℃, 260℃, 255℃, 255℃, 255℃, 260℃, and 260℃, respectively. The screw speed is controlled at 300-350 rpm, and the vacuum exhaust pressure is controlled at ≤-0.06 MPa.

[0103] All pressures mentioned refer to gauge pressure.

[0104] The screw assemblies of the twin-screw extruder along the material flow direction are as follows: 36 / 18, 36 / 18, 36 / 18, 36 / 18, 36 / 18, 36 / 18, 36 / 18, 36 / 18, 24 / 12, K30 / 7 / 36, K45 / 5 / 24, K45 / 5 / 24, K45 / 5 / 24, K60 / 4 / 16, K45 / 5 / 12, 48 / 48, 48 / 48, 48 / 24, 36 / 36, K30 / 7 / 36, K45 / 5 / 24, K45 / 5 / 24. 24 / 24, K45 / 5 / 24, K45 / 5 / 24, 36 / 36, 36 / 36, 36 / 36, 36 / 36, 36 / 36, K45 / 5 / 24, 36 / 36, S / 1, ZME7.5 / 15, ZME7.5 / 15, ZME7.5 / 15, 36 / 36, S / 1, ZME7.5 / 15, ZME7.5 / 15, S / 1, 36 / 36, 36 / 36, 36 / 36, 36 / 36, 24 / 24, 24 / 24, 24 / 24. The total length of the screw assembly is 1145 mm. This specific screw assembly allows for a more complete reaction, maximizing the dispersion of glass fiber and flame retardant. The resulting product has excellent mechanical and flame retardant properties and can be used in high-strength, halogen-free flame-retardant automotive parts.

[0105] Table 1 shows the formulation of the PA1012 / MXD6 composite material, including multiple experiments and control experiments conducted in proportion to the desired ratio.

[0106]

[0107] The normalization methods used in the embodiments are all prior art min-ma normalization;

[0108] The sampling point configuration module is used to calculate and group the meshing cycles of adjacent threaded elements. Multiple sensors are evenly installed inside the threaded barrel, and sampling points are configured on the threaded element for each sensor, including:

[0109] Reference Figure 2 The threaded element is used to configure the screw. The screw is obtained by fitting the threaded element onto the metal rod. The two screws are referred to as screw one and screw two, respectively.

[0110] For any threaded element:

[0111] Obtain the pitch of the threaded element and rotational speed ;

[0112] Calculate axial thrust speed ;

[0113] Get the length of the threaded element Calculate the transmission cycle of the threaded element. ;

[0114] The transmission cycles of adjacent threaded elements located on screw one and screw two are denoted as follows: and ;

[0115] Adjacent threaded elements are screwed together, take and Least Common Multiple As the meshing cycle, since the two elements have different cycles when the twin screws mesh, the common multiple of the two cycles is required to ensure sampling alignment, which is the shortest time for both to reset their rotational states simultaneously.

[0116] If adjacent threaded elements rotate in opposite directions, existing technologies have methods for calculating the transmission cycle;

[0117] On any screw, adjacent threaded elements with equal meshing periods are grouped together;

[0118] Each set of threaded elements is equipped with a single sensor, with the sensor positioned directly opposite the centerline of the two screws;

[0119] Set the number of samples taken by the sensor during the engagement cycle. The sampling frequency of the sensor ;

[0120] At sampling time The rotation phase of the threaded element corresponding to sampling point k is The threaded element rotates by an angle per unit time. Adding the initial phase gives the current rotation phase, where, This represents the initial phase of the threaded element. For modulo operation, in this embodiment, refer to Figure 3 The threaded element rotates around its axis, and the sampling points collected by the sensor differ at different times. The sampling time is calculated. The sampling point can be determined by combining the rotational phase with the known sensor position.

[0121] The sampling and periodic feature extraction module is used to generate the time series for each sampling point, collect smoke density and gas component concentration in real time, and extract the periodic feature parameters of the sampling points, including:

[0122] In this embodiment, the sensors include an optical smoke density sensor for measuring smoke density and a gas composition sensor;

[0123] The smoke density S(k) at sampling point k in each engagement cycle is obtained by the sensor and then denoised.

[0124] Plot a two-dimensional curve of smoke density, and follow... By dividing the two-dimensional curve into units on the horizontal axis, multiple sets of periodic smoke densities are obtained, and the peak value of the smoke density S(k) for each period is obtained. ;

[0125] The peak value can be calculated using existing techniques such as local maxima, sliding window, and minimum peak spacing;

[0126] Set peak threshold Obtain within any period Maximum smoke density Extract the corresponding smoke density phase ;

[0127] Mapping Given a unit vector in the complex plane, calculate the phase concentration of the smoke density. , It is a unit vector. The number of sampling points, when The closer it is to 1, the more concentrated the phase is, indicating stable periodic adhesion, which helps to determine the consistency and volatility of the material's movement cycle.

[0128] Obtain arbitrary sampling points of the next set of threaded elements along the material transport direction. Obtain sampling points smoke density ;

[0129] Calculate sampling point k and sampling point Maximizing discrete cross-correlation , For the smoke to be transferred from sampling point k to sampling point Duration Used to measure smoke density According to different durations Alignment smoke density to similar and ;

[0130] for The smoke density at sampling point k at time k. for Time sampling point Smoke density;

[0131] Calculate the transmission velocity of smoke density along the material transport direction. , For sampling point k to sampling point Euclidean distance.

[0132] Real-time acquisition of smoke density and gas component concentration, extraction of periodic characteristic parameters of sampling points, and also includes:

[0133] Obtain the composition of all gases at sampling point k collected by the sensor;

[0134] For any gas composition:

[0135] Obtain the concentration of gas components Calculate the average concentration at sampling point k according to the time series. ;

[0136] Obtain the concentration difference of adjacent gas components in the time series. ;

[0137] Calculate the rate of increase in concentration .

[0138] The adhesion determination and positioning module is used to calculate the comprehensive adhesion index based on periodic characteristic parameters and perform material adhesion determination, including:

[0139] For sampling point K throughout the entire detection process:

[0140] Calculate the difference in concentration increase rate and then calculate the mean. ;

[0141] Obtain the torque variation of each threaded element within the threaded element group and calculate the average value. ;

[0142] Obtain the current change of the screw ;

[0143] The periodic characteristic parameter ,include , , The periodic feature parameters are normalized and updated to the normalized values.

[0144] Set the feature correlation matrix The feature correlation matrix is ​​used to set a weight coefficient for each element in the periodic feature parameters to complete feature interaction;

[0145] Using the feature correlation matrix For periodic characteristic parameters Cross-weighted , ;

[0146] Mapping the cross-weighted result to a nonlinear function , ,in, To adjust the parameters and control the steepness of the response, For the cumulative effect of multiple features, The expression is converted into exponential form to ensure... ;

[0147] Will Normalize and update to the normalized value;

[0148] Calculate the combined adhesion index upstream and downstream of the sampling point ,in, The nonlinear function at any sampling point along the material transport direction. These are spatial adjustment parameters used to control the degree of influence from the neighborhood.

[0149] The comprehensive adhesion index integrates multiple source signals, including gas component concentration, smoke density, torque, current, phase concentration, and transmission speed. After cross-weighting through a feature correlation matrix, a normalized response is obtained through nonlinear mapping and neighborhood smoothing. The comprehensive adhesion index not only eliminates the dimensional differences of each feature but also mathematically reflects the consistency of multiple features and physically corresponds to the energy accumulation state of the adhesion process.

[0150] For any sampling point within the group, obtain the smoke density difference between the sampling points. ;

[0151] Set adhesion index threshold Sum and difference thresholds

[0152] If sampling points exist simultaneously and If so, it can be preliminarily determined that there is material adhering to it;

[0153] An increase in the concentration of gas components indicates that harmful or decomposition products are locally retained, suggesting that local pyrolysis / decomposition has occurred in the material or that gas outflow is obstructed.

[0154] Reduced smoke density: When there is adhesion and blockage, the optical path may be blocked by a solid layer or the flow field may change, resulting in a decrease in the scattering / transmission signal measured at the detection point (relative to the previous peak value), or the upstream may be blocked, resulting in a momentary low value detected downstream.

[0155] The simultaneous presence of both indicates the presence of chemical products and obstruction of the flow field, which is used to preliminarily determine whether material adhesion exists.

[0156] Obtain the comprehensive adhesion index of all sampling points within a single group and calculate the mean. ;

[0157] Continue to determine If the material is found to be attached to a single set of threaded elements, this will be used as the final determination.

[0158] The process of calculating the adhesion quality after locating the adhesion position includes:

[0159] Along the material transport direction, if there are consecutive single sets of threaded elements with material attachment, then the axial attachment section is located as consecutive single sets of threaded elements with material attachment.

[0160] Obtain the phase of the maximum smoke density at each sampling point in the axial attachment section, and calculate the mean value. ;

[0161] Set phase spread ;

[0162] Calculate the phase concentration interval ;

[0163] By acquiring sampling points where the smoke density phase exceeds the phase concentration interval, the circumferential attachment section is obtained;

[0164] When there is an adhesion layer around the screw or barrel, two key changes occur:

[0165] Optical obstruction and airflow disturbance: The attachment section causes uneven local scattering paths, resulting in an abnormal decrease or shift in the smoke density signal within this angular range; that is, at this angle (phase), the smoke density is no longer aligned with the main period.

[0166] Signal periodic disruption: Due to local obstruction causing gas flow delay, the periodic waveform will show "phase delay" or "jump"; from a timing perspective, it means that the signal phase drift of some sampling points exceeds the normal concentration range.

[0167] Therefore, sampling points whose phases fall outside the concentrated interval actually represent that the smoke density response at the current rotation angle no longer corresponds to the normal cycle, indicating that there is physical blockage or attached disturbance at that angle.

[0168] Sampling points for the attached material are located by the axial attachment section and the circumferential attachment section;

[0169] Setting the material adhesion coefficient This is used to reflect the sensitivity of changes in smoke density to the transformation of mass, and its unit is 1. The experiment was calibrated by measuring the mass of the attached material and the smoke density at the sampling points under a fixed duration of 10 minutes, based on the calculated comprehensive adhesion index. The material adhesion coefficient was then calculated accordingly. The experimental environment simulated the real production environment.

[0170] Calculate the mass of the attached material at the sampling point. , This represents the total sampling time.

[0171] The decision-making and maintenance action module is used to execute decision-making and maintenance actions for the twin-screw extruder based on a set threshold according to the comprehensive adhesion index, adhesion quality, and gas component concentration, including:

[0172] Setting gas component thresholds ;

[0173] Obtain the concentration of gaseous components harmful to the human body. If the sampling point k If this occurs, immediately suspend the twin-screw extruder and issue an alarm;

[0174] During material processing, pyrolysis, or flame retardancy, the concentration changes of toxic, irritating, or potentially hazardous volatile components are collected and identified in real time, including but not limited to carbon monoxide, nitrogen oxides, ammonia, amines, halogenated compounds, and phosphorus oxides.

[0175] The comprehensive adhesion index, adhesion quality, and gas component concentration are normalized and updated to normalized values;

[0176] Set weight coefficients ;

[0177] Calculate risk score ;

[0178] Set risk threshold and duration threshold ;

[0179] like And lasting longer than If necessary, the twin-screw extruder should be shut down for maintenance.

[0180] like And lasting longer than If so, notify maintenance personnel to check.

[0181] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0182] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A smoke density and toxicity detection system developed based on flame-retardant reinforced halogen-free nylon materials, characterized in that, include: The formulation parameter configuration module is used to configure the formulation for developing flame-retardant reinforced halogen-free nylon materials and to set the formulation parameters. The sampling point configuration module is used to calculate and group adjacent threaded elements, and to uniformly install multiple sensors inside the threaded barrel, configuring sampling points on the threaded element for each sensor. The sampling and periodic feature extraction module is used to generate the time series of each sampling point, collect smoke density and gas component concentration in real time, and extract the periodic feature parameters of the sampling points; The adhesion determination and positioning module is used to calculate the comprehensive adhesion index based on the periodic characteristic parameters, perform material adhesion determination, locate the adhesion position, and calculate the adhesion quality. The decision and maintenance action module is used to perform decision and maintenance actions for the twin-screw extruder based on a set threshold according to the comprehensive adhesion index, adhesion quality and gas component concentration.

2. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 1, characterized in that, The formula parameter configuration module is used to configure the formula for developing flame-retardant reinforced halogen-free nylon materials and to set the formula ratios, including: The weight of the flame-retardant reinforced halogen-free nylon material is set to 1. The formulation and weight of the flame-retardant reinforced nylon halogen-free material are as follows: PA1012 resin 0.25-0.50, MXD6 resin 0.20-0.40, wollastonite whiskers 0.25-0.40, compound flame retardant 0.15-0.20, toughening agent 0.005-0.05, glass fiber 0.15-0.30, antioxidant 0.005-0.02, lubricant 0.005-0.02; The PA1012 resin has a melting temperature of 260±5℃ and a density of 1.03g / cm3; The MXD6 resin has a melting temperature of 280-300℃ and a density ≥1.32g / cm3; The wollastonite whiskers are obtained by surface treatment with a coupling agent, are white, have an aspect ratio of 2-20, and a density of 2.9 g / cm3. The toughening agent is maleic anhydride-modified polyolefin elastomer. The compound flame retardants are aluminum hypophosphite 0.10-0.12 and melamine polyphosphate 0.05-0.

08.

3. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 1, characterized in that, The sampling point configuration module is used to calculate and group adjacent threaded elements, uniformly install multiple sensors inside the threaded barrel, and configure sampling points on the threaded element for each sensor, including: The threaded element is used to configure the screw, and the two screws are respectively referred to as screw one and screw two; The screw one and screw two are placed side by side adjacent to each other and parallel to the horizontal plane; For any threaded element: Obtain the pitch of the threaded element and rotational speed ; Calculate axial thrust speed ; Get the length of the threaded element Calculate the transmission cycle of the threaded element. ; The transmission cycles of adjacent threaded elements located on screw one and screw two are denoted as follows: and ; Adjacent threaded elements are screwed together, take and Least Common Multiple As the meshing cycle; On any screw, adjacent threaded elements with equal meshing periods are grouped together; Each set of threaded elements is equipped with a single sensor, with the sensor positioned directly opposite the centerline of the two screws; Set the number of samples taken by the sensor during the engagement cycle. The sampling frequency of the sensor ; At sampling time The rotation phase of the threaded element corresponding to sampling point k is ,in, This represents the initial phase of the threaded element. Modulo operation.

4. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 1, characterized in that, The sampling and periodic feature extraction module is used to generate a time series for each sampling point, collect smoke density and gas component concentration in real time, and extract periodic feature parameters of the sampling points, including: For any sensor: The smoke density S(k) at sampling point k in each engagement cycle is obtained by the sensor and then denoised. Plot a two-dimensional curve of smoke density, and follow... By dividing the two-dimensional curve into units on the horizontal axis, multiple sets of periodic smoke densities are obtained, and the peak value of the smoke density S(k) for each period is obtained. ; Set peak threshold Acquire within any period Maximum smoke density Extract the corresponding smoke density phase ; Mapping Given a unit vector in the complex plane, calculate the phase concentration of the smoke density. , It is a unit vector. The number of sampling points; Obtain arbitrary sampling points of the next set of threaded elements along the material transport direction. Obtain sampling points smoke density ; Calculate sampling point k and sampling point Maximizing discrete cross-correlation , For the smoke to be transferred from sampling point k to sampling point Duration Used to measure smoke density According to different durations Alignment smoke density to similar and ; for The smoke density at sampling point k at time k. for Time sampling point Given the smoke density, calculate the transmission velocity of the smoke density along the material transport direction. , For sampling point k to sampling point Euclidean distance.

5. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 4, characterized in that, The real-time acquisition of smoke density and gas component concentration, and the extraction of periodic characteristic parameters of sampling points, also include: Obtain the composition of all gases at sampling point k collected by the sensor; For any gas composition: Obtain the concentration of gas components Calculate the average concentration at sampling point k according to the time series. ; Obtain the concentration difference of adjacent gas components in the time series. ; Calculate the rate of increase in concentration .

6. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 5, characterized in that, The adhesion determination and positioning module is used to calculate the comprehensive adhesion index based on periodic characteristic parameters and perform material adhesion determination, including: For sampling point K throughout the entire detection process: Calculate the difference in concentration increase rate and then calculate the mean. ; Obtain the torque variation of each threaded element within the threaded element group and calculate the average value. ; Obtain the current change of the screw ; The periodic characteristic parameter ,include , , The periodic feature parameters are normalized and updated to the normalized values. Set the feature correlation matrix The feature correlation matrix is ​​used to set a weight coefficient for each element in the periodic feature parameters to complete feature weighting; Using the feature correlation matrix For periodic characteristic parameters Cross-weighted , ,in, Dimensions and same; Mapping the cross-weighted result to a nonlinear function , ,in, To adjust the parameters and control the steepness of the response, For the cumulative effect of multiple features, The expression is converted to exponential form to ensure... ; Will Normalize and update to the normalized value; Calculate the combined adhesion index upstream and downstream of the sampling point ,in, The nonlinear function at any sampling point along the material transport direction. These are spatial adjustment parameters used to control the degree of influence from the neighborhood. For any sampling point within the group, obtain the smoke density difference between the sampling points. ; Set adhesion index threshold Sum and difference thresholds ; If sampling points exist and If so, it can be preliminarily determined that there is material adhering to it; Obtain the comprehensive adhesion index of all sampling points within a single group and calculate the mean. ; Continue to determine If so, it is determined that the material is attached to a single set of threaded elements.

7. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 6, characterized in that, The process of calculating the adhesion quality after locating the adhesion position includes: Along the material transport direction, if there are consecutive single sets of threaded elements with material attachment, then the axial attachment section is located as consecutive single sets of threaded elements with material attachment. Obtain the phase of the maximum smoke density at each sampling point in the axial attachment section, and calculate the mean value. ; Set phase spread ; ,in, Mean A unit vector mapped to the complex plane; Calculate the phase concentration interval ; By acquiring sampling points where the smoke density phase exceeds the phase concentration interval, the circumferential attachment section is obtained; Sampling points for the attached material are located by the axial attachment section and the circumferential attachment section; Setting the material adhesion coefficient It is used to reflect the sensitivity of changes in smoke density to the transformation of material mass; Calculate the mass of the material attached to the sampling point , This represents the total sampling time.

8. The smoke density and toxicity detection system developed based on flame-retardant reinforced nylon halogen-free material according to claim 7, characterized in that, The decision-making and maintenance action module is used to perform decision-making and maintenance actions for the twin-screw extruder based on a set threshold according to the comprehensive adhesion index, adhesion quality, and gas component concentration, including: Setting gas component thresholds ; Obtain the concentration of gaseous components harmful to the human body. If sampling point k If this occurs, immediately suspend the twin-screw extruder and issue an alarm; The comprehensive adhesion index, adhesion quality, and gas component concentration are normalized and updated to normalized values; Set weight coefficients ; Calculate risk score ; Set risk threshold and duration threshold ; like And lasting longer than If necessary, the twin-screw extruder should be shut down for maintenance. like And lasting longer than If so, notify maintenance personnel to check.

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